1. Field of the Invention
The present invention relates to a valve operating system in an internal combustion engine, in which a support shaft is mounted to extend between first and second support walls included in a rocker arm, and the rocker arm is urged by an urging means in a direction to bring a roller into rolling contact with a valve operating cam.
2. Description of the Related Art
A valve operating system of the above type is already known from Japanese Patent Publication No. 2-50286 and the like. In such known valve operating system, a receiving portion is provided at a widthwise central portion of the rocker arm in a direction parallel to the axis of a rocker shaft on which the rocker arm is swingably supported. However, due to the fact that the receiving portion is positioned at the central portion of the rocker arm, despite the provision of the roller, the structure of the rocker arm is complicated, and the size of the rocker arm is increased, resulting in an increased weight.